Method for cleaning surface of stainless steel

ABSTRACT

A method for cleaning a surface of stainless steel includes: a rinsing step, in which a stainless steel tube having carbon residues is subjected to surface cleaning; a disposition step, in which the tube is disposed into an electrolytic tank containing therein a stainless steel cylinder and positive and negative electrodes of a power source are respectively connected to the tube and the cylinder; an electrolyte preparation step, in which phosphoric acid and sulfuric acid are mixed and then added with glycerin to prepare an electrolyte, which is then added into the tank; an electricity supplying step, in which electrical power is supplied to the tube and the cylinder with the current density flowing through the electrolyte, the temperature, and time period of supplying electricity being properly set; and a cleaning step, in which the electrolyte removes carbon residues from a surface of the tube and polishes the surface.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to a method for cleaning a surface of stainless steel, and more particularly to a stainless steel surface cleaning method that removes carbon residues from the stainless steel surface and also polishes the stainless steel surface.

DESCRIPTION OF THE PRIOR ART

Taiwan Patent Publication No. 200841995 discloses a method for polishing a surface of round metal work piece, in which a shaped round metal work piece removed out of a furnace is first subjected to surface roughening by a surface roughing processing set and then the surface-roughened round metal work piece is polished by a polishing set so as to realize polished surface finishing of the round metal work piece. However, processing a round metal work piece by first roughening the surface and thus polishing provides only limited effects of surface cleaning, smoothening, and polishing. Thus, it is desired to have further improvement in this respect.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a method for cleaning a surface of stainless steel, comprising the following steps:

a rinsing step, in which a stainless steel tube to be polished that has carbon residues is subjected to surface cleaning by applying a cleaning agent and is then rinsed with distilled water and dried;

a disposition step, in which the stainless steel tube to be polished is disposed into an electrolytic tank in which a stainless steel cylinder is arranged and a positive electrode of an electrical power source is connected to the stainless steel tube to be polished and a negative electrode of the electrical power source is connected to the stainless steel cylinder;

an electrolyte preparation step, in which phosphoric acid (H₃PO₄) is mixed with sulfuric acid (H₂SO₄) and the mixture is cooled down and then added with glycerin to prepare an electrolyte, which is then added into the electrolytic tank;

an electricity supplying step, in which electrical power is supplied to the stainless steel tube to be polished and the stainless steel cylinder with the electrical current density flowing through the electrolyte, the temperature, and time period of supplying electricity being properly set; and

a cleaning step, in which the electrolyte carries out removal of carbon residues from a surface of the stainless steel tube to be polished and polishing of the surface to thereby realize smoothening, polishing and cleaning of the surface of stainless steel.

The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself; all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.

Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a method for cleaning a surface of stainless steel according to the present invention.

FIG. 2 is a schematic view showing a stainless steel tube to be polished.

FIG. 3 is a schematic view showing preparation of mixture of electrolyte according to the present invention.

FIG. 4 is a schematic view showing the present invention.

FIG. 5 is a schematic view showing a finished product of stainless steel tube according to the present invention after polishing.

FIG. 6 is a schematic view showing another embodiment of the present invention that provides enhanced throughput.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.

Referring to FIGS. 1 and 2, the present invention provides a method for cleaning a surface of stainless steel, comprising the following steps:

a rinsing step (reference numeral 1), in which a stainless steel tube to be polished 5 that has carbon residues 11 is subjected to surface cleaning by applying a cleaning agent, the stainless steel tube to be polished 5 is then rinsed with distilled water, and the stainless steel tube to be polished 5 is then dried;

a disposition step (reference numeral 3), in which, as shown in FIG. 4, the stainless steel tube to be polished 5 that has been rinsed in the rinsing step 1 is disposed into an electrolytic tank 32 in which a stainless steel cylinder 33 is arranged and a positive electrode 311 of an electrical power source 31 is connected to the stainless steel tube to be polished 5 and a negative electrode 312 of the electrical power source 31 is connected to the stainless steel cylinder with the positive electrode 311 and the negative electrode 312 being spaced by a fixed distance, which is preferably 10-20 mm, to ensure excellent effect of electricity conduction;

an electrolyte preparation step (reference numeral 2), in which, as shown in FIG. 3, phosphoric acid (H₃PO₄) 21 is used as a base liquid, which is added with sulfuric acid (H₂SO₄) for forming a mixture 23, wherein the ratio between the phosphoric acid 21 and the sulfuric acid 22 is 2:1 (V/V), and wherein the mixture of phosphoric acid 21 and sulfuric acid 22 generating heat, so that a cool water bath is applied to cool down the mixture 23, and the mixture 23 is then added with glycerin 24 of 18-32 volume % to prepare an electrolyte 25, which is then added into the electrolytic tank 32;

an electricity supplying step (reference numeral 30), in which electrical power is supplied to the stainless steel tube to be polished 5 and the stainless steel cylinder 33 with the electrical current density flowing through the electrolyte 25 being set to 18-32 mA/cm², temperature being set to 25-55° C., and time period of supplying electricity being set to 10-20 minutes, whereby the positive electrode 311 and the negative electrode 312 of the electrical power source 31, when supplied with electricity, generate ions, which makes the electrolyte 25 to penetrate into pores in the stainless steel tube to be polished 5 to clean and remove dirt concealed in the pores and the supply of electricity through the electrolyte 25 enhances of result cleaning by speed up the cleaning operation; and

a cleaning step (reference numeral 4), in which the electrolyte 25 carries out removal of carbon residues 11 from the surface of the stainless steel tube to be polished 5 and polishing of the surface so as to thereby realize smoothening, polishing and cleaning of the surface 51 of stainless steel, as shown in FIG. 5.

As shown in FIG. 6, to increase the throughput of cleaning or polishing operation, a plurality of electrolytic tanks 32 is provided and electrolyte 25 that is allowed to flow through the electrolytic tanks 32 is collected, as indicated at 62, to be pressurized as indicated at 61 so that the electrolyte 25 can be re-supplied to the electrolytic tanks 32, whereby the electrolyte 25 is allow to cyclically circulate and the throughput of the cleaning and polishing operation of the stainless steel tubes is raised.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 

1. A method for cleaning a surface of stainless steel, comprising the following steps: a rinsing step, in which a stainless steel tube to be polished that has carbon residues is subjected to surface cleaning by applying a cleaning agent and is then rinsed with distilled water and dried; a disposition step, in which the dried stainless steel tube to be polished is disposed into an electrolytic tank in which a stainless steel cylinder is arranged and a positive electrode of an electrical power source is connected to the stainless steel tube to be polished and a negative electrode of the electrical power source is connected to the stainless steel cylinder; an electrolyte preparation step, in which phosphoric acid is mixed with sulfuric acid and cooled and then added with glycerin of 18-32 volume % to prepare an electrolyte, which is then added into the electrolytic tank, wherein mixture ratio between the phosphoric acid and the sulfuric acid is 2:1 (V/V); an electricity supplying step, in which electrical power is supplied to the stainless steel tube to be polished and the stainless steel cylinder with the electrical current density flowing through the electrolyte, the temperature, and time period of supplying electricity being properly set; and a cleaning step, in which after the stainless steel tube to be polished and the stainless steel cylinder are supplied with electrical power, the electrolyte carries out removal of carbon residues from the surface of the stainless steel tube to be polished and polishing of the surface.
 2. The method according to claim 1, wherein the electrical current density flowing through the electrolyte is set to 18-32 mA/cm², the temperature is set to 25-55° C., and the time period of supplying electricity is set to 10-20 minutes.
 3. The method according to claim 1, wherein the positive electrode and the negative electrode are spaced by a fixed distance, which is 10-20 mm.
 4. The method according to claim 1, wherein said plug member is capable of being plugged into a conventional lamp socket. 